Opinions: Would you rather have a Princeton Reverb or a Deluxe Reverb?

[Mike_J]

As mentioned in an earlier post I am going to help a friend, a complete newb, build a new amp.  He had a blackface Princeton Reverb that he regrets selling so he would like to build one to replace it.  I have never heard a Princeton Reverb that I know of but I love the sound of a Deluxe Reverb.

Doug sells the chassis, faceplates and back plates, among most of the other parts you would need to build either amp.  I don't see the cost difference as very significant.  Need a choke and a few other parts for the DR but they don't add up to a lot of money.  Because of the parts Doug carries and I previously mentioned the build would end up with a very professional appearance.

I now think I need a Deluxe Reverb of my very own.  In addition to giving your opinion as to whether you like the DR or PR better, can someone explain why Doug's AB763 layout does not have a roach in the vibrato circuit.  I may be missing it but I don't think so.  I am sure there is a very good reason for it.

Thank
Mike

[alerich]

The roach is there. Connected to the wiper of the 50K RA intensity pot.

http://el34world.com/charts/Schematics/files/fender/Fender_Deluxe-Reverb-AB763-schematic.pdf

I prefer the Princeton Reverb. I prefer the bias vary trem to the roach trem. I prefer the concertina style PI to the long tail PI and I like a 10" speaker as opposed to the 12" inch. The speaker and PI are subjective things but the trem is a big deal to me.

[sluckey]

I prefer the DR.

can someone explain why Doug's AB763 layout does not have a roach in the vibrato circuit.

Hoffman's AB763 is not an exact copy of Fender's AB763. His circuit does not use a roach. Instead, he uses a bias vary trem circuit from the 6G16 VIBROVERB.

[Mike_J]

The roach is there. Connected to the wiper of the 50K RA intensity pot.

http://el34world.com/charts/Schematics/files/fender/Fender_Deluxe-Reverb-AB763-schematic.pdf

I prefer the Princeton Reverb. I prefer the bias vary trem to the roach trem. I prefer the concertina style PI to the long tail PI and I like a 10" speaker as opposed to the 12" inch. The speaker and PI are subjective things but the trem is a big deal to me.

Alerich

Sorry I was not clear about what I was asking.  I have attached Doug's AB763 - 2 Channel layout.  That is the circuit I was asking about in my head.  Sluckey answered it in the previous reply.  Now that you know the DR is going to have the trem of the famous Vibroverb and of course you could put a 10" speaker in it if that is what you prefer are you still sticking to the concertina style PI versus the LTPI? 

Thanks
Mike

[Ed_Chambley]

I built a Princeton Reverb using Black Face Deluxe Iron.  Had to make some component changes due to the Deluxe OT being much beefier.  I can run 6v6's and 6L6.  It has 2 10's.  Has the concertina with the Ampeg (Paul C) mod.  Raised voltages on the PI as well.

It has the bias vary trem, nice verb and a effects loop.  It is my main small amp and has been for a few years.  I play it and the Vox AC15 together mostly.  Basically I took each part of an amp I had a preference for.  I used some Twin values to clean up the lower volumes.

I have a 65 Deluxe already, if I hadn't I probably would have built the Deluxe, but I do use the other one more.

[Mike_J]

I built a Princeton Reverb using Black Face Deluxe Iron.  Had to make some component changes due to the Deluxe OT being much beefier.  I can run 6v6's and 6L6.  It has 2 10's.  Has the concertina with the Ampeg (Paul C) mod.  Raised voltages on the PI as well.

It has the bias vary trem, nice verb and a effects loop.  It is my main small amp and has been for a few years.  I play it and the Vox AC15 together mostly.  Basically I took each part of an amp I had a preference for.  I used some Twin values to clean up the lower volumes.

I have a 65 Deluxe already, if I hadn't I probably would have built the Deluxe, but I do use the other one more.

Ed

Do you remember what component changes had to be made due to the beefier OT?  Not familiar with the Paul C mod but I am sure it is on the net somewhere.  Could you provide a brief description of what it does?

I have an AB763 already with Tweed Bassman Iron.  Has an old sheet of maple plywood I made the cabinet out of which I think favorably impacts the tone of the amp.  It is in pieces waiting for me to recover the cabinet but will now get the Hoffman AB763 - 2 Channel circuit with the Vibroverb vibrato.  The cabinet is designed to accept either a 12" or 15" speaker.  Has a Jensen reissue P12N in it now that will be changed to a EVM-15L.  Might be my next project.

Good news.  My friend that I am helping build this amp for is great at sound recording so sound clips from my Sluckey inspired Plexi/800 should be forthcoming in the near future.

Thanks
Mike

[EL34]

The AB763 information page on the library page explains why I use bias vibrato


Go to the AB763 boards and look for AB763 circuit information page

http://el34world.com/schematics.htm#Hoffman_AB763_Two_Channel_

[jjasilli]

Per my last post in the companion thread, I think a DR has better OD tone than a Princeton. 

[eleventeen]

"Per my last post in the companion thread, I think a DR has better OD tone than a Princeton"


Some of that phenom has to be 1: the better output iron driving the 2: larger, 12" vs 10" speaker. 


Come to think of it I have never really messed with a stock Princeton. The SF AB763 one I have arrived broken and (30+ years ago) and I just  directly hotrodded it to dual 6L6 with a Dynaco 35-watt power & output transformer, and installed an Altec 12" speaker! They were plentiful, cheap, and not well regarded back then. So it was never any kind of choked-down amp.

[2deaf]

The two channel varieties have a fundamental difference from the one channel ones.  The two channel has two plates mixed together at the PI and the one channel doesn't.  The effect on the sound is another one of those things that I think makes a lot of difference and other people don't acknowledge it at all.  The difference that two plates mixed together has on the sound is more apparent to me in the high overdrive amps, but it is also a definite effect on these low drive Fenders.

I have attached a couple of examples of how I use the effect.

[HotBluePlates]

Disclosure: I've owned several blackface and silverface Princeton Reverbs, but never owned a Deluxe Reverb.

I think I'd prefer the sound of a 12" speaker over a 10" (which is funny given the succession of Princetons I've had, as well as my tweed Super copy). It is probably easier to find great 12" speakers than great 10" speakers.

The Deluxe Reverb's OT is 6.6kΩ compared to the Princeton's 8kΩ, which allows greater output power for the same output tubes and B+ voltage. I'd want the amp to have a Mid pot, which neither have.

An additional ~250kΩ pot wired as a variable resistor between the Mid pot and ground could allow a lot of mid-boost at the expense of reducing the tone stack's effect.

I only need 1 channel, unless the 2nd channel was an overdrive channel of some sort.

Any version of tremolo is handy, though I'm most likely to get it by way of a pedal these days. Within the constraints of application and output power, you can't beat a VibroChamp's bias-vary trem, and with the Princeton and Hoffman AB763 bias-vary close behind (though they don't tend to pump the way the VibroChamp does with no input signal).

So I'd probably prefer a single-channel Deluxe Reverb with a couple added controls and the Hoffman-style tremolo.

[Ed_Chambley]

I built a Princeton Reverb using Black Face Deluxe Iron.  Had to make some component changes due to the Deluxe OT being much beefier.  I can run 6v6's and 6L6.  It has 2 10's.  Has the concertina with the Ampeg (Paul C) mod.  Raised voltages on the PI as well.

It has the bias vary trem, nice verb and a effects loop.  It is my main small amp and has been for a few years.  I play it and the Vox AC15 together mostly.  Basically I took each part of an amp I had a preference for.  I used some Twin values to clean up the lower volumes.

I have a 65 Deluxe already, if I hadn't I probably would have built the Deluxe, but I do use the other one more.

Ed

Do you remember what component changes had to be made due to the beefier OT?  Not familiar with the Paul C mod but I am sure it is on the net somewhere.  Could you provide a brief description of what it does?

I have an AB763 already with Tweed Bassman Iron.  Has an old sheet of maple plywood I made the cabinet out of which I think favorably impacts the tone of the amp.  It is in pieces waiting for me to recover the cabinet but will now get the Hoffman AB763 - 2 Channel circuit with the Vibroverb vibrato.  The cabinet is designed to accept either a 12" or 15" speaker.  Has a Jensen reissue P12N in it now that will be changed to a EVM-15L.  Might be my next project.

Good news.  My friend that I am helping build this amp for is great at sound recording so sound clips from my Sluckey inspired Plexi/800 should be forthcoming in the near future.

Thanks
Mike

Changed the bypass of v1a to 10uf/1500, the next one was changed to 4.7uf.  Reduced the coupling caps to half of the stock value.  Changed the NFB, making it stiffer, but is switchable.  Installed a Raw control a bypass on the tonestack.  The Tonestack is a TMB with the Middle being 25K.

I made it dual bias because I could, no other reason.  I made it a 2 10 and had Weber recone the speakers to the Silver Bell and Blue PUP.  They started as CTS Horseshoe Alnico.  They are 20 watts.

I used a Mercury Multitap Black Face OT.  Wattage output is just under 21 watts with 6V6.  Have not measured 6L6, but there is a considerable output change.  I would guess it is over 30 watts with the 6l6.  What I was trying to do was get close to a minature Twin.  I really did not want it to breakup like a Deluxe.  Not that that is bad.  I love it, but I already own one.

The amp has a Super 5F4 quality, but not distorting.  I prefer the distorted sound of the 6l6, but it is getting loud.

This is part of my main small rig which is this amp with a loop and Modualtion only on this amp.  I use the AC15 Normal channel (EF86) and it is used for overdrive/distortion.  It has a Celestion Blue.  I call it my micro stack.  I have retired most of my others.

Paul c mod is nothing more than biasing the PI I think.  Search for it, but if you do this build use a 4k7 resistor.  It works better in the AA1164 circuit.  Some also do the Stokes and move the PI up a node.  I changed the rail resistors added a node and used a choke capable of handling the plates like in a 5F4.  I can't remember the hammond choke I added, but it is large.  I left the screen choke on it as well.  The filter caps are 40/20/20/20 can. 

Like I said, if you go this route I will dig up where the voltages ended up.  They are actually a little higher than a Deluxe in the preamp due to what I ended up with the dropping resistors, but with a SS rectifier the power section is higher as well.

I wanted a cleanish amp.

I cant remember everything I did tweaking, but will be happy to look if you decide to build it.